The increase in efficiency and cost reduction in electric steel production in arc furnaces are significantly limited by the life of the refractory lining.
To increase the life of the refractory lining for the furnace vessel and the furnace cover, basically two approaches are possible. The traditional refractory construction materials are completely dispensed with and replaced by water-cooled linings.
In the publication of the firm of Mannesmann; Demag "Water-carrying Lining of Electric Arc Melting Furnaces," undated, an arc furnace is described that is equipped with such a water-cooled vessel wall.
Water-cooled elements (pipes or boxes) are embedded in the ceramic refractory construction materials of the walls of the furnace vessel. As a result, on the one hand, a mechanical and, on the other hand, a thermal stabilization of the refractory construction materials is achieved. Such a furnace is the object of the Swiss patent application No. 552/83-3 of 1/29/83.
Both variants greatly increase the stability of the furnace vessel walls against thermal effects and thus contribute to more economical steel production, but they simultaneously involve the danger that leakages can occur in the water-cooling system unnoticed by the furnace service crew. These leakages permit free access of water or steam into the interior of the furnace chamber and may trigger oxyhydrogen explosions with incalculable consequences.
Regardless of this, water destroys a hearth of an arc furnace lined, for example, with dolomite refractory construction materials. It is especially dangerous if the water in a temporarily cold furnace does not evaporate immediately, collects in the hearth lined with ceramic refractory construction materials, and comes into contact with molten metal in the subsequent melting process. Sensors to monitor the water cooling system are very expensive and merely permit indication of inadequate functioning of all parts of the cooling system.